It's good, it's not great.
It has structural and pacing problems, the bad guys plan is confusing and the whole 'Rising' aspect happens twice to pad out the runtime and that's really annoying.
I don't want to come down too hard on this movie because I honestly did enjoy it. I was just underwhelmed. But the good stuff is still good; the acting is top notch, action scenes are jaw dropping, the ending and climax is Oscar worthy and the music is some of Hans Zimmer's best work, which is saying a lot.
Should you buy it? In the words of Bane: "Of course". I mean you can't buy the other two and not buy this one, it wouldnt feel right. Just don't get too hyped for it. You most likely will but I can't stop you or won't try.
All in all, good movie and hugely enjoyable.